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5150 Joker

macrumors member
Original poster
Oct 24, 2006
82
0
Davis, California
I'm new to the Mac/OSX platform and I haven't seen any mention of a popular disk defragment program yet. Anyone here have some suggestions?
 

Warbrain

macrumors 603
Jun 28, 2004
5,702
293
Chicago, IL
I was reading that once the disk reaches around 80% full things start slowing down and a disk defrag program becomes neccessary even for OSX.

Part of the reasoning that I think that could be right is that there isn't as much space for virtual memory then. But I've never read that anywhere. Someone might have more knowledge on that than me.
 

ghall

macrumors 68040
Jun 27, 2006
3,771
1
Rhode Island
I use iDefrag, though defrag is not really necessary unless your working with large files (I think it's over 40MB). OS X does have a built-in defragmenter, but even that needs a little help sometimes.
 

markw10

macrumors 6502
Sep 4, 2006
371
0
Do you have to defragment Hard Drives?

I am used to having to Defragment hard drives on the PC. Is this necessary on the Mac and if so is there a good program to buy to do it or does this come with the computer?
 

mleary

macrumors regular
Sep 13, 2006
145
0
I was reading that once the disk reaches around 80% full things start slowing down and a disk defrag program becomes neccessary even for OSX.

You only have to worry if you get down to 1GB or so available space so the OS can create new swap files if it needs to. OS X creates swap files in 80MB increments so even 1GB of available space should be fine.
 

knome

macrumors 6502
Sep 7, 2006
332
0
onyX does optimizations but i think i heard somewhere that it is not necessary because of UNIX.
 

WildCowboy

Administrator/Editor
Staff member
Jan 20, 2005
18,390
2,829
Wow...it's the day of defrag. A similar question was last asked an hour ago.

Basically, unless you work with large files (like heavy video editing), there is no real need to defrag, as the OS automatically does it for small files.
 

Eraserhead

macrumors G4
Nov 3, 2005
10,434
12,250
UK
I am used to having to Defragment hard drives on the PC. Is this necessary on the Mac and if so is there a good program to buy to do it or does this come with the computer?

Mac's automatically defrag small files but large files (>50MB or so) can still get fragmented, assuming you keep a decent backup it is actually quicker to just reformat your HD and restore it from backup than it is to run a defrag. (And it's pretty painless compared to windows too.)
 

yellow

Moderator emeritus
Oct 21, 2003
16,018
6
Portland, OR
I love how people think that...

And what's wrong with that? It happens to be true.

You only have to worry if you get down to 1GB or so available space so the OS can create new swap files if it needs to. OS X creates swap files in 80MB increments so even 1GB of available space should be fine.

This is incorrect.

OS X (Tiger/Panther specifically, things were different in pre-10.3*), creates dynamically sized swap files.
And they are based on normal computer bit sizes, 64MB, 128MB, 256MB, 512MB, 1024MB.. I've never seen them get any larger than 1GB.

Code:
ls -lh /var/vm
total 2097152
drwx--x--x   20 root  wheel       680B Oct 17 10:29 app_profile
-rw------T    1 root  wheel        64M Oct 27 17:01 swapfile0
-rw------T    1 root  wheel        64M Oct 31 12:05 swapfile1
-rw------T    1 root  wheel       128M Oct 31 15:46 swapfile2
-rw------T    1 root  wheel       256M Nov  1 15:01 swapfile3
-rw------T    1 root  wheel       512M Nov  1 15:28 swapfile4

And I would not suggest allowing your disk to fill to the point where you have 1GB left. If you have that little an amount of disk space, invest in an external drive or delete some pr0n. :)

*: Pre-Panther swap sizes were static. I don't remember the exact sizes, but I think they were all in 64MB increments.
 

Bern

macrumors 68000
Nov 10, 2004
1,854
1
Australia
I've had Macs since the late 80's and have never defragged the HD. I do photo editing and digital artwork and have never had a problem. It's just another urban legend developed by Windows users and more so these days since more and more Windows users are going Mac.

Having said that I had to defrag my HD for the first time last night... that is the Windows XP partition created from Bootcamp :p
 

Warbrain

macrumors 603
Jun 28, 2004
5,702
293
Chicago, IL
I've had Macs since the late 80's and have never defragged the HD. I do photo editing and digital artwork and have never had a problem. It's just another urban legend developed by Windows users and more so these days since more and more Windows users are going Mac.

Having said that I had to defrag my HD for the first time last night... that is the Windows XP partition created from Bootcamp :p

I would defrag in OS 9 just because it was part of the series of checks that Norton ran on the computer whenever I had issues, which seemed to be quite often.
 

yellow

Moderator emeritus
Oct 21, 2003
16,018
6
Portland, OR

Except... do they have a product to sell you? TechToolPro prehaps?
Does it include a defrag util perhaps? Oh it does?
Does it seem in their best interest to post something like this? Perhaps? :)

Sorry, it's the cynical color in me. Yes, this article comes up a lot (it used to be a forum post, if I remember correctly).

Ultimately, it's up to the user. A defrag ISN'T necesary. As noted in the article disks are so fast, that a defragged disk sometime only has the PERCEPTION of being "faster". But if you WANT or think you NEED a defrag, AFAIK, there's TTP and iDefrag out there. That's all.
 

cube

Suspended
May 10, 2004
17,011
4,972
According to what they wrote, if you leave 15% of the partition free you wouldn't have to buy anything.
 

yellow

Moderator emeritus
Oct 21, 2003
16,018
6
Portland, OR
Weeeellll not implicitly, but yes you could take that away from it...

Micromat strongly recommends that you always leave at least 15% of any HFS+ volume as free space. If an HFS+ volume is more than 85% full and is heavily fragmented, any further data added to the volume can result in irreparable damage to the disk directory.

It's a bit misleading.
 

cube

Suspended
May 10, 2004
17,011
4,972
It's not about speed. It's about safety. It's harder to recover the data from a fragmented disk if it goes bad.
 

yellow

Moderator emeritus
Oct 21, 2003
16,018
6
Portland, OR
It's not about speed. It's about safety. It's harder to recover the data from a fragmented disk if it goes bad.

This is why we back up, no? If one has a good back up, there's no need to care about recovering data from a fragmented disk that go bad.
 
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